"Today the ZFS on Linux project reached an important milestone with the official 0.6.1 release! Over two years of use by real users has convinced us ZoL is ready for wide scale deployment on everything from desktops to super computers."

It's not a matter of whether it's ready, it's a matter of whether it's any good:

ZFS CLI tools are a dream to use where as Btrfs CLI tools are a pig. ZFS snapshotting is child's play, rolling back snapshots on Btrfs is just awkward in comparison (particularly if the volume is /). There's a few other design decisions behind Btrfs that annoy me, but I really don't want to get into a rant about it tonight

I just really don't like Btrfs one bit so if I had to run a CoW file system like Btrfs or ZFS then I'd sooner run a non-Linux OS and have ZFS than run Btrfs just for the sake of running Linux.

Thankfully I'm just as at home on FreeBSD and Solaris as Linux, so I don't feel as chained to the Linux ecosystem as some *nix administrators do.